OVF: simplify expected return values of transport functions.

Transport functions (transport_iso9660 and transport_vmware_guestinfo)
would return a tuple of 3 values, but only the first was ever used
outside of test.  The other values (device and filename) were just
ignored.

This just simplifies the transport functions to now return content
(in string format) or None indicating that the transport was not found.

2 files changed, 33 insertions, 57 deletions

diff --git a/cloudinit/sources/DataSourceOVF.py b/cloudinit/sources/DataSourceOVF.py
index 891d6547..3a3fcdf6 100644
--- a/cloudinit/sources/DataSourceOVF.py
+++ b/cloudinit/sources/DataSourceOVF.py
@@ -236,7 +236,7 @@ class DataSourceOVF(sources.DataSource):
                   ('iso', transport_iso9660)]
             name = None
             for name, transfunc in np:
-                (contents, _dev, _fname) = transfunc()
+                contents = transfunc()
                 if contents:
                     break
             if contents:
@@ -464,8 +464,8 @@ def maybe_cdrom_device(devname):
     return cdmatch.match(devname) is not None
 
 
-# Transport functions take no input and return
-# a 3 tuple of content, path, filename
+# Transport functions are called with no arguments and return
+# either None (indicating not present) or string content of an ovf-env.xml
 def transport_iso9660(require_iso=True):
 
     # Go through mounts to see if it was already mounted
@@ -477,9 +477,9 @@ def transport_iso9660(require_iso=True):
         if not maybe_cdrom_device(dev):
             continue
         mp = info['mountpoint']
-        (fname, contents) = get_ovf_env(mp)
+        (_fname, contents) = get_ovf_env(mp)
         if contents is not False:
-            return (contents, dev, fname)
+            return contents
 
     if require_iso:
         mtype = "iso9660"
@@ -492,27 +492,27 @@ def transport_iso9660(require_iso=True):
             if maybe_cdrom_device(dev)]
     for dev in devs:
         try:
-            (fname, contents) = util.mount_cb(dev, get_ovf_env, mtype=mtype)
+            (_fname, contents) = util.mount_cb(dev, get_ovf_env, mtype=mtype)
         except util.MountFailedError:
             LOG.debug("%s not mountable as iso9660", dev)
             continue
 
         if contents is not False:
-            return (contents, dev, fname)
+            return contents
 
-    return (False, None, None)
+    return None
 
 
 def transport_vmware_guestinfo():
     rpctool = "vmware-rpctool"
-    not_found = (False, None, None)
+    not_found = None
     if not util.which(rpctool):
         return not_found
     cmd = [rpctool, "info-get guestinfo.ovfEnv"]
     try:
         out, _err = util.subp(cmd)
         if out:
-            return (out, rpctool, "guestinfo.ovfEnv")
+            return out
         LOG.debug("cmd %s exited 0 with empty stdout: %s", cmd, out)
     except util.ProcessExecutionError as e:
         if e.exit_code != 1:
diff --git a/tests/unittests/test_datasource/test_ovf.py b/tests/unittests/test_datasource/test_ovf.py
index e4af0fa3..349d54cc 100644
--- a/tests/unittests/test_datasource/test_ovf.py
+++ b/tests/unittests/test_datasource/test_ovf.py
@@ -19,6 +19,8 @@ from cloudinit.sources.helpers.vmware.imc.config_custom_script import (
 
 MPATH = 'cloudinit.sources.DataSourceOVF.'
 
+NOT_FOUND = None
+
 OVF_ENV_CONTENT = """<?xml version="1.0" encoding="UTF-8"?>
 <Environment xmlns="http://schemas.dmtf.org/ovf/environment/1"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -127,8 +129,8 @@ class TestDatasourceOVF(CiTestCase):
         retcode = wrap_and_call(
             'cloudinit.sources.DataSourceOVF',
             {'util.read_dmi_data': None,
-             'transport_iso9660': (False, None, None),
-             'transport_vmware_guestinfo': (False, None, None)},
+             'transport_iso9660': NOT_FOUND,
+             'transport_vmware_guestinfo': NOT_FOUND},
             ds.get_data)
         self.assertFalse(retcode, 'Expected False return from ds.get_data')
         self.assertIn(
@@ -143,8 +145,8 @@ class TestDatasourceOVF(CiTestCase):
         retcode = wrap_and_call(
             'cloudinit.sources.DataSourceOVF',
             {'util.read_dmi_data': 'vmware',
-             'transport_iso9660': (False, None, None),
-             'transport_vmware_guestinfo': (False, None, None)},
+             'transport_iso9660': NOT_FOUND,
+             'transport_vmware_guestinfo': NOT_FOUND},
             ds.get_data)
         self.assertFalse(retcode, 'Expected False return from ds.get_data')
         self.assertIn(
@@ -194,8 +196,8 @@ class TestDatasourceOVF(CiTestCase):
         with mock.patch(MPATH + 'util.read_dmi_data', return_value='!VMware'):
             with mock.patch(MPATH + 'transport_vmware_guestinfo') as m_guestd:
                 with mock.patch(MPATH + 'transport_iso9660') as m_iso9660:
-                    m_iso9660.return_value = (None, 'ignored', 'ignored')
-                    m_guestd.return_value = (None, 'ignored', 'ignored')
+                    m_iso9660.return_value = NOT_FOUND
+                    m_guestd.return_value = NOT_FOUND
                     self.assertTrue(ds.get_data())
                     self.assertEqual(
                         'ovf (%s/seed/ovf-env.xml)' % self.tdir,
@@ -215,8 +217,8 @@ class TestDatasourceOVF(CiTestCase):
         with mock.patch(MPATH + 'util.read_dmi_data', return_value='VMWare'):
             with mock.patch(MPATH + 'transport_vmware_guestinfo') as m_guestd:
                 with mock.patch(MPATH + 'transport_iso9660') as m_iso9660:
-                    m_iso9660.return_value = (None, 'ignored', 'ignored')
-                    m_guestd.return_value = (None, 'ignored', 'ignored')
+                    m_iso9660.return_value = NOT_FOUND
+                    m_guestd.return_value = NOT_FOUND
                     self.assertTrue(ds.get_data())
                     self.assertEqual(
                         'vmware (%s/seed/ovf-env.xml)' % self.tdir,
@@ -246,10 +248,7 @@ class TestTransportIso9660(CiTestCase):
         }
         self.m_mounts.return_value = mounts
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-        self.assertEqual("mycontent", contents)
-        self.assertEqual("/dev/sr9", fullp)
-        self.assertEqual("myfile", fname)
+        self.assertEqual("mycontent", dsovf.transport_iso9660())
 
     def test_find_already_mounted_skips_non_iso9660(self):
         """Check we call get_ovf_env ignoring non iso9660"""
@@ -272,10 +271,7 @@ class TestTransportIso9660(CiTestCase):
         self.m_mounts.return_value = (
             OrderedDict(sorted(mounts.items(), key=lambda t: t[0])))
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-        self.assertEqual("mycontent", contents)
-        self.assertEqual("/dev/xvdc", fullp)
-        self.assertEqual("myfile", fname)
+        self.assertEqual("mycontent", dsovf.transport_iso9660())
 
     def test_find_already_mounted_matches_kname(self):
         """Check we dont regex match on basename of the device"""
@@ -289,10 +285,7 @@ class TestTransportIso9660(CiTestCase):
         # we're skipping an entry which fails to match.
         self.m_mounts.return_value = mounts
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-        self.assertEqual(False, contents)
-        self.assertIsNone(fullp)
-        self.assertIsNone(fname)
+        self.assertEqual(NOT_FOUND, dsovf.transport_iso9660())
 
     def test_mount_cb_called_on_blkdevs_with_iso9660(self):
         """Check we call mount_cb on blockdevs with iso9660 only"""
@@ -300,13 +293,9 @@ class TestTransportIso9660(CiTestCase):
         self.m_find_devs_with.return_value = ['/dev/sr0']
         self.m_mount_cb.return_value = ("myfile", "mycontent")
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-
+        self.assertEqual("mycontent", dsovf.transport_iso9660())
         self.m_mount_cb.assert_called_with(
             "/dev/sr0", dsovf.get_ovf_env, mtype="iso9660")
-        self.assertEqual("mycontent", contents)
-        self.assertEqual("/dev/sr0", fullp)
-        self.assertEqual("myfile", fname)
 
     def test_mount_cb_called_on_blkdevs_with_iso9660_check_regex(self):
         """Check we call mount_cb on blockdevs with iso9660 and match regex"""
@@ -315,25 +304,17 @@ class TestTransportIso9660(CiTestCase):
             '/dev/abc', '/dev/my-cdrom', '/dev/sr0']
         self.m_mount_cb.return_value = ("myfile", "mycontent")
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-
+        self.assertEqual("mycontent", dsovf.transport_iso9660())
         self.m_mount_cb.assert_called_with(
             "/dev/sr0", dsovf.get_ovf_env, mtype="iso9660")
-        self.assertEqual("mycontent", contents)
-        self.assertEqual("/dev/sr0", fullp)
-        self.assertEqual("myfile", fname)
 
     def test_mount_cb_not_called_no_matches(self):
         """Check we don't call mount_cb if nothing matches"""
         self.m_mounts.return_value = {}
         self.m_find_devs_with.return_value = ['/dev/vg/myovf']
 
-        (contents, fullp, fname) = dsovf.transport_iso9660()
-
+        self.assertEqual(NOT_FOUND, dsovf.transport_iso9660())
         self.assertEqual(0, self.m_mount_cb.call_count)
-        self.assertEqual(False, contents)
-        self.assertIsNone(fullp)
-        self.assertIsNone(fname)
 
     def test_mount_cb_called_require_iso_false(self):
         """Check we call mount_cb on blockdevs with require_iso=False"""
@@ -341,13 +322,11 @@ class TestTransportIso9660(CiTestCase):
         self.m_find_devs_with.return_value = ['/dev/xvdz']
         self.m_mount_cb.return_value = ("myfile", "mycontent")
 
-        (contents, fullp, fname) = dsovf.transport_iso9660(require_iso=False)
+        self.assertEqual(
+            "mycontent", dsovf.transport_iso9660(require_iso=False))
 
         self.m_mount_cb.assert_called_with(
             "/dev/xvdz", dsovf.get_ovf_env, mtype=None)
-        self.assertEqual("mycontent", contents)
-        self.assertEqual("/dev/xvdz", fullp)
-        self.assertEqual("myfile", fname)
 
     def test_maybe_cdrom_device_none(self):
         """Test maybe_cdrom_device returns False for none/empty input"""
@@ -393,12 +372,11 @@ class TestTransportVmwareGuestinfo(CiTestCase):
 
     rpctool = 'vmware-rpctool'
     with_logs = True
-    not_found = (False, None, None)
     rpctool_path = '/not/important/vmware-rpctool'
 
     def test_without_vmware_rpctool_returns_notfound(self, m_subp, m_which):
         m_which.return_value = None
-        self.assertEqual(self.not_found, dsovf.transport_vmware_guestinfo())
+        self.assertEqual(NOT_FOUND, dsovf.transport_vmware_guestinfo())
         self.assertEqual(0, m_subp.call_count,
                          "subp should not be called if no rpctool in path.")
 
@@ -407,7 +385,7 @@ class TestTransportVmwareGuestinfo(CiTestCase):
         m_which.return_value = self.rpctool_path
         m_subp.side_effect = util.ProcessExecutionError(
             stdout="", stderr="No value found", exit_code=1, cmd=["unused"])
-        self.assertEqual(self.not_found, dsovf.transport_vmware_guestinfo())
+        self.assertEqual(NOT_FOUND, dsovf.transport_vmware_guestinfo())
         self.assertEqual(1, m_subp.call_count)
         self.assertNotIn("WARNING", self.logs.getvalue(),
                          "exit code of 1 by rpctool should not cause warning.")
@@ -421,7 +399,7 @@ class TestTransportVmwareGuestinfo(CiTestCase):
         """
         m_which.return_value = self.rpctool_path
         m_subp.return_value = ('', '')
-        self.assertEqual(self.not_found, dsovf.transport_vmware_guestinfo())
+        self.assertEqual(NOT_FOUND, dsovf.transport_vmware_guestinfo())
         self.assertEqual(1, m_subp.call_count)
 
     def test_notfound_and_warns_on_unexpected_exit_code(self, m_subp, m_which):
@@ -429,7 +407,7 @@ class TestTransportVmwareGuestinfo(CiTestCase):
         m_which.return_value = self.rpctool_path
         m_subp.side_effect = util.ProcessExecutionError(
             stdout=None, stderr="No value found", exit_code=2, cmd=["unused"])
-        self.assertEqual(self.not_found, dsovf.transport_vmware_guestinfo())
+        self.assertEqual(NOT_FOUND, dsovf.transport_vmware_guestinfo())
         self.assertEqual(1, m_subp.call_count)
         self.assertIn("WARNING", self.logs.getvalue(),
                       "exit code of 2 by rpctool should log WARNING.")
@@ -439,9 +417,7 @@ class TestTransportVmwareGuestinfo(CiTestCase):
         m_which.return_value = self.rpctool_path
         content = fill_properties({})
         m_subp.return_value = (content, '')
-        self.assertEqual(
-            (content, self.rpctool, "guestinfo.ovfEnv"),
-            dsovf.transport_vmware_guestinfo())
+        self.assertEqual(content, dsovf.transport_vmware_guestinfo())
         self.assertEqual(1, m_subp.call_count)
 
 #